Interactive home information system for distributing video picture information to television viewers over a fiber optic telephone system

ABSTRACT

An interactive multimedia system with distributed processing and storage of video picture information and associated data and sound in nodes disposed throughout a cable television distribution system. The nodes are coupled to the feeder cable of the cable distribution system. Each node in the system receives a substantially identical copy of the interactive video picture information and related data from a regional processing center. The nodes can receive the Video picture information through the cable television distribution system or externally of the cable system. The users at home televisions associated with a particular node interact directly with the video picture information in that node, rather than with the information stored in the regional processing center or some other remote location, which enables the system to quickly display photographic quality images and complex graphics, as well as sound, at the users&#39; televisions in response to commands received by the users. The nodes can also be used for decompressing compressed television programming and distributing the decompressed programming to home televisions connected to the system.

This is a continuation application of U.S. Ser. No. 07/754,932, filedSep. 10, 1991, now U.S. Pat. No. 5,720,420, which is acontinuation-in-part of U.S. application Ser. No. 07/589,205, filed Sep.27, 1990, now U.S. Pat. No. 5,093,718, entitled "INTERACTIVE HOMEINFORMATION SYSTEM", the disclosure of which is herein incorporated byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an interactive multimedia system forsupplying information to users in their homes and, more particularly, toan interactive multimedia system with distributed information processingand storage which is hardwired to the user through existing cabletelevision systems.

2. Description of the Related Art

Distributed processing and storage are relatively new concepts in datamanagement and--because of the various technological hurdles--have notbeen considered until now for application to the field of videotex. TheProdigy® information service, which is now being marketed nationwide bySears and IBM, claims to use a distributed database architecture.However, that system only distributes the database to regional mainframecomputers. Their underlying technology--as with all other currentvideotex technology--still relies completely on the maintenance ofcontinuous, real-time, two-way communication of a personal computer (orother terminal) in the home with a mainframe computer at some remotelocation. Nearly all videotex services use phone lines and modems tolink the two, though some experiments with two-way cable TV and othermedia have been attempted. These existing systems have numerouslimitations.

Since each user of a traditional videotex system is directly connectedto a central mainframe when on-line, this central computer must becapable of simultaneously handling the many subscribers it gets duringprime usage periods, while it may sit almost idle the rest of the time.As the number of users increases, additional large computers must beadded to the system at great expense. Any problem with the centralcomputer or the communications net linking it to the users can cause theentire system to cease functioning.

The speed with which information may be retrieved from such systems islimited to the speed with which the central computer can recognize theusers' requests and locate the information in its central data storagemedia. Even the largest and fastest of central computers cannot overcomethe severe limitations of how quickly information may be carried by thephone lines or other media that connect it to the user. Phone lines havea narrow bandwidth and can carry only a limited amount of information atany one time. For example, it takes 8 to 10 seconds for a centralcomputer to send a screen full of just text information to a userterminal over a telephone line, assuming a typical communications speedof 2400 baud. A complex graphic or photographic quality image could takeat least hour per image.

The newer Integrated Services Digital Network (ISDN) and fiber opticcable technologies will provide greater information transmissioncapability for businesses, but these technologies will not be wired intoa large number of individual homes for at least another ten years.Moreover, even using high speed fiber optics connecting a centralcomputer to a home terminal, the largest of computers cannot keep upwith an entire city of users especially during prime time. As anexample, the largest airline reservation system can only process 8000transactions per second.

This bandwidth problem has never been adequately addressed by thoseworking in the field because--until very recently--all computerinterfaces were just character-based or used very low resolutionalphamosaic style displays utilizing protocols such as NAPLPS orTeletel. While simple character-based information may be transmittedover phone lines relatively easily, the resulting display is difficultto interpret and use. Even simple alphamosaic displays take longenough--about 8 seconds--to transmit over a phone line that the level ofinteractively declines and, with the low quality of the display, thesystems tend to become uninteresting and awkward to use. After thenovelty wears off, the typical consumer finds that the difficulty ofusing such systems to obtain useful information, coupled with their slowspeed and uninteresting graphics, makes other more traditional ways ofobtaining information, i.e., printed information, more attractive.

Graphic user interfaces, particularly those using the high resolution,"photorealistic" displays are far more interesting and easier to use,but require vastly greater amounts of data to be transmitted in order togenerate interesting screen images that will respond to the user'srequests quickly. What has not been addressed by workers in the videotexfield is that, while wide bandwidth transmission media remain verylimited and/or expensive, the relative costs of memory media such asmagnetic disk drives, dynamic random access chips (DRAMs) and other waysof storing data have been dropping quickly, as has the cost of fastmicroprocessors that can efficiently access and display data stored inthe media. This suggests that a highly distributed architecture wouldovercome the bandwidth limitations and provide a cost effective and veryfast information delivery system. The system of the present inventionexploits these ongoing technological changes and thus overcomes theabove-noted problems in the videotex field.

SUMMARY OF THE INVENTION

The present invention, unlike prior art systems, provideseasy-to-understand photographic quality images and full-motion video,accompanied by sound (speech and music), as well as traditional text andgraphical information. This combination is commonly referred to in theart as a "multimedia" PG,6 system. This is possible only because thedata needed by the user of the present invention is stored locally inthe memory of the processing module or node that is serving theindividual home or small group of homes over the existing broadbandmedia of the coaxial TV cable drop that goes into each household anddirectly to the television set. Because each local node can handle allof the households attached to it, and since it is independent of anycentral computer except for daily updates, the system is also veryreliable and economically scalable. Whether two households or twohundred thousand households use the system simultaneously will notimpact performance, and the system will continue to work and provideinformation to end users even if the source of updates, usually from thecentral processing computer, is shut down for quite some time.

Briefly, the system of the present invention includes:

a regional processing center for assembling and processing theinformation to be transmitted over the television cable distributionsystem; and

at least one node coupled to the cable television distribution systemfor capturing and storing the processed and assembled information, thenode being associated with at least one of the home televisions.

Preferably, many cable television subscribers share the informationstored in a node. A subscriber can display and interact with theinformation stored in the associated node by communicating commands tothe node. Since each of the nodes in the cable television distributionsystem contains a substantially identical copy of the informationtransmitted by the regional processing center, the subscriber interactsdirectly with the information stored in the node, and not with theinformation stored in the regional processing center.

Each of the nodes in the system is coupled to a feeder cable of thecable television distribution system at a location immediately after thecable line extender amplifier (approximately every quarter mile).Typically, there are from one to ten taps of four or more outputs eachbetween any two line extender amplifiers on a feeder cable, all of whichare served by one node in the present invention. The nodes transmit theinformation to the home televisions at television channel frequenciesunused by the cable distribution system for transmitting ordinary cabletelevision programming. These frequencies are typically above the lastused cable TV channel.

Feeder inserters are used to connect the nodes to the feeder cable. Thefeeder inserters include a low pass filter for blocking information fromany upstream nodes, while permitting the video frequencies used by thecable system for ordinary cable television programming to pass throughdownstream unattenuated.

The nodes output information to their associated home televisions over aplurality of frequency channels. A home interface controller coupled toeach home television receives and descrambles a channel from the node,preferably on the next available frequency channel (on a contentionbasis). The home interface controller communicates back to the node on alow band frequency on a polled basis. In this contention embodiment,each of the home interface controllers contains electronics whichunscrambles only the channel assigned to it for viewing by the user. Inother embodiments of the invention, the controllers communicate withtheir associated node on a non-contention basis.

As mentioned above, the user retrieves selected multimedia informationby sending commands back to the node. These commands travel to the nodeover a return path using the existing cable television wire, just as themultimedia information itself sent from the node to the home televisionstravel over the existing cable TV wire.

Preferably, users of the system are provided with a remote control touchpad device, available with or without a full typewriter style keyboard,for inputting user commands into the home interface controller coupledto their television. Alternately, or in addition, the home interfacecontrollers are adapted to receive user commands from a conventional PCkeyboard, via an infrared interface attached to the keyboard.

Yet another option is to provide users with printers for printing hardcopies of information received from the node, including tickets toentertainment events or coupons for merchandise discounts, etc.

Preferably, the system is configured to allow user responses to betransmitted from the subscriber terminals to a selected merchant. Theuser responses return to the selected merchants after passing up thesubscriber cable to the node, then via a telephone line attached to thenode (or the upstream nodes send user responses downstream to an endnode, which has the telephone line). Optionally, as an addedconvenience, an autodialer device may be provided to dial the telephoneof the user to allow the user to speak directly to a system advertiser,for example the seller of an item described in a classified ad on thesystem.

Advantageously, the nodes of the present invention can also be used fordecompressing compressed television programming and distributing thedecompressed programming to users connected to the system.

The importance of the present invention to the electronic informationdistribution and multimedia industries is that it can deliverphotographic quality images, as well as full-motion video with sound, tomillions of homes simultaneously. The system can meet peek demandperiods, and most importantly, can deliver information with a look andfeel equivalent to what the home viewer has come to expect from networktelevision, i.e., interesting colorful 3-D graphics, photographicquality images and smoothly rendered text. This contrasts to existingsystems with limited graphics that look like video games and havejagged, poorly rendered text. Prior art videotex systems could not domore, or look better, without adopting the approach outlined in thissummary, and set forth in greater detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention willbecome apparent when the following text is read in conjunction with theaccompanying drawings in which:

FIG. 1 illustrates the regional network architecture of the invention,where a regional facility receives and preprocesses data for all thecities in the region and distributes the preprocessed data to respectivecable TV systems, and where the data is in turn broadcast to nodes foraccess by individual home interface controllers;

FIG. 2 illustrates the hardware of the present invention coupled to atypical cable TV system.

FIGS. 2A-2C illustrate various alternative configurations for couplingnodes to a cable TV system;

FIG. 3 illustrates a diagram showing the node of the present inventionconnected to a typical cable TV feeder and showing the connection of anode to a cable TV subscriber home;

FIG. 4 is diagram showing the bandwidth usage of the system on a typicalTV system;

FIG. 5 is a schematic of a feeder inserter which is used to couple eachnode into the cable feeder;

FIGS. 6A and 6B, collectively, represent a schematic diagram of a node;

FIG. 7 is a schematic diagram of an extender module which is used to addmore channels to a node;

FIG. 8 is a schematic diagram of a home interface controller whichinterfaces between a node and a user's TV set; FIG. 8A is a blockdiagram of the frame grabber circuitry of the home interface controller;

FIG. 9 is a diagram of a second embodiment of the invention n which atap interface is used to reduce the amount of electronics in each homeinterface controller;

FIG. 10 is a schematic diagram of a node in a second embodiment of theinvention;

FIGS. 11A and 11B, collectively, represent a schematic diagram of thetap interface used in the second embodiment of the invention in acontention configuration;

FIG. 12 a is a schematic diagram of the tap interface used in the secondembodiment of the invention in a non-contention configuration;

FIG. 13 is a schematic diagram of the simplified home interfacecontroller used in the second embodiment of the invention;

FIG. 14 is a schematic diagram of a still further embodiment of theinvention in which all the node electronics are in the home interfacecontroller of each user;

FIG. 15 is a schematic of the touch pad remote control device preferablyused in the system of the present invention;

FIGS 16-18 illustrate, respectively, an optional PC keyboard interface,a home interface controller telephone interface, and video inputelectronics for inputting user-created video to create classified ads;

FIG. 19 shows the operation of the invention to remotely controlelectronic products in a subscriber's home;

FIG. 20 shows an embodiment of the invention in which information issent to the nodes from an external source;

FIGS. 21-25 illustrate various bandwidth utilization schemes fordistributing decompressed television programming using the nodes of thepresent invention;

FIG. 26 illustrates an embodiment in which the nodes of the inventionare disposed in remote stations of a telephone company fiber opticsystem;

FIG. 27 illustrates an embodiment in which RF distribution nodes areutilized and the bulk of the nodes electronics and storage iscentralized in a node at the headend;

FIG. 28A illustrates the simplified electronics of a distribution node;

FIG. 28B illustrates the electronics for video compression/decompressionin a node; and

FIG. 28C illustrates the feeder inserter electronics for a distributionnode.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS I. System Overview

The present invention is a distributed computer system that offers avariety of consumer-oriented information and advertisement sources. Theuser interacts with the system using a remote control device and viewsthe system output on an unmodified home television set as just anotherTV channel.

A small home interface controller containing a remote control receiversits atop the TV set and is connected to the cable TV wiring in serieswith the user's television. This unit transmits user remote controlactions back up the subscriber cable TV drop to a local computer--calleda node--which is wired to the cable line outside the home.

The node computer directly interacts with the user and has stored, on aninternal storage medium such as a hard disk, a complete copy of all dataof the entire system. This node computer is complete in all respects anddoes not have to refer back to a central computer to complete userinformation requests. The node computers are placed throughout the cablesystem on poles, underground, or in apartment building basements andeach serves about 40 homes apiece.

II. Data Flow Through the System

Referring now to the drawings, where like reference numbers indicatelike elements, and specifically referring first to FIG. 1, data for thesystem originates from various contracted information providers orservice providers. Data from these providers is received via computermodem over telephone lines 2 by regional processing center .Advertisements and information listings, such as classified ads and TVlistings, come into the regional center 4 throughout the day. Thisinformation is processed and customized into data "magazines" for eachcable system. A processed data magazine is ready to go by the nextmorning and is transmitted via computer modem over telephone lines 6 toa computer 8 placed in the headend 10 of the target cable system.

The headend computer 8 acts as a store and forward device to receivethis data and rebroadcast it to all of the nodes 12 throughout the cablesystem 14. The headend computer 8 transmits the data updates at apreferred data rate of 9600 bps or greater. The entire set of updates istransmitted repeatedly until the next day. This ensures that randomnoise induced data errors not corrected by the block error correctioncodes are corrected on the next pass of the data set.

It should be noted that since the headend computer 8 acts merely as abuffer, it is not a required element of the system; i.e., the systemcould operate with the data being sent from regional processing center 4directly to the nodes 12. However, the headend computer 8 is included inthe preferred embodiment of the invention since it provides an extralevel of backup storage in event of a failure of a regional processingcenter.

The home user interacts with the system using a infrared remote controldevice. The remote control signal is received by a set-top unit called ahome interface controller (HIC) 16. HIC 16 sends the user commandsreceived from the remote control back up the cable drop to node 12outside the home.

Some of the information and services carried on the system offerinteractive sessions with the user, such as purchasing tickets for thetheater, music or sports events, as well as home shopping opportunities.The user's choices are relayed from the node 12 along the feeder cableto the last downstream node (the "end node"), and from there back to theheadend computer 8 via a telephone line 18 connected to the end node.The headend computer 8 then relays user response packets back to theregional center 4 over telephone lines 20. The regional processingcenter 4 converts user response packets into a format expected by theparticular service provider and relays the user data back to therespective provider via computer modem over telephone line 22.

III. Information Content and System Database

Typical information carried on the system includes: TV listings for amonth in advance; classified ads; Yellow Pages type ads and listings,local restaurant guide; local entertainment listings; and miscellaneousinformation such as: current sports scores, financial news, trafficconditions, current weather radar image and forecasts.

The various sources of information and advertisements will originate indigitized video format for pictorial information, digitized sound forradio, and ASCII or EBCDIC text for textual information. Listings andadvertisements will be transmitted to regional processing center 4 viacomputer modem from the supplier's computer (computer to computer link).

The regional processing center 4 converts and normalizes incomingdigitized pictures, digitized sound and text into system standardizedformat. The normalized data is then moved into an object-orienteddatabase. Each object in the database is made up of one or more of thefollowing components: one or more digitized photographic orcomputer-graphic images (e.g. sequences of images for animation);digitized sound tracks; a hypertext-like script language (to define,based on user input, when and how to show images and play audio);textual information (such as body text of a classified ad or companyaddress and hours of business); location coordinates of enterprise orbusiness (used to compute distance of business from users home); andthesaurus entries (used to store associations between objects).

Once normalized and stored in the object database, the data are groupedby category (TV 10 listings, classified ads, etc.). The grouped(categorized) data are then further processed to establish relevantassociations or meaning amongst the data objects. The associations,where relevant, are added to the respective objects in the form ofthesaurus entries so that the associations travel with the data object.

The hypertalk-like script language, mentioned above, is used to guidethe user interface program in translating user commands from the remotecontrol into actions on the user's TV screen. For example, these actionsmight include displaying an image and playing an audio track when thehome user, using the remote control, positions an on-screen cursor ontop of a particular icon, word, or other image and then presses the"PLAY" button on the remote control.

The data objects of the system database are advertisements in the formof layered or stacked information which allow a viewer to dig into thestack (like turning pages in a catalog) to reveal levels of informationthat interest the viewer. The layered advertisement is a videoequivalent of a consumer brochure or catalog where the viewer can flipthrough at will to view relevant sections.

The data structure of the layered advertisement can be used for any typeof information carried by the network. The advertisements carried by thesystem can be text only, such as a simple classified ad for a used car,or could contain a picture of the used car for sale. The system canstore and display in layered fashion an entire catalog for a departmentstore with hundreds of images and audio tracks in one object module.Alternatively, the system can store as an object module a list ofinformation, such as a month of TV listings. If desired, that month ofTV listings can contain selected images of actors of scenes from moviesor TV shows that are displayed along with audio tracks when the viewerbrowses through the TV listings.

To summarize, the system utilizes a generalized storage methodology topackage diverse kinds of information from audio/visual full-motionsegments to static images to textual lists of information. The layereddata structure presents a uniform structure to the decoding and displaylogic which the user interacts with.

Information and service providers, ad agencies, newspaper addepartments, etc. are supplied with video-graphics workstations based onpopular personal computer technology. These workstations containproprietary and commercial software to enable third parties to createfinished, broadcast quality advertisements combining short full-motionsegments, still images, and audio as desired. These advertisements canthen be transmitted via modem to the regional processing center forpreparation for inclusion on the system database.

IV. Overview of the Distributed Architectural of the System

The regional processing center 4 is responsible for the processing andassembly of the complete sets of information (called magazines) for eachcable system. Once the data is assembled and processed at the regionalcenter 4, it is ready for viewing. The data needs only to be transferredto nodes 12 for access by the home users.

The nodes 12 are the end point of the distributed architecture of thesystem of the present invention. Each node 12 can serve up to about 60homes on a contention basis (with an optional node extension module 124discussed below), where up to 31 of the 60 homes can use the nodeindependently and simultaneously. The home user interacts with node 12through a home interface controller 16 using an infrared remote controldevice 40 (discussed later).

The node 12 receives and stores on an internal mass storage medium allof the advertisement data broadcast by the headend computer 8. The dailybroadcasts from the regional center to the computer 8 and then from theheadend computer 8 to the nodes 12 consist only of changes to the nodedatabase. These changes consist of additions of new data, deletion ofexpired data, and changes to existing data. These updates will affectapproximately 20 percent of the total database, for a given day,although the system is designed to accommodate 100% change every night.

The entire database that a user interacts with is local to the user. Afull bandwidth TV channel is available from the node 12 to each home. Acable system may use a thousand or more nodes. This is in contrast withpast and present videotex systems communicating over telephone lineswith 1/1000 the bandwidth of a TV channel and a singular centralcomputer to serve an entire city of tens of thousands or more.

V. System Interface to Cable TV System

Referring to FIGS. 1 and 2, some advertisements are created atinformation suppliers and ad agencies offices on workstations. Datalistings, such as TV listings, movie listings, and classified ads areimported from information providers via computer modem over telephonelines 2 into the regional processing center 4 and converted intoadvertisement object modules.

Once normalized, the object modules are grouped together fortransmission to their respective cable TV system. The data magazine(group of advertisements) is transmitted over leased line 6 at apreferred data rate of 56 kbps (although the data rate can be anywherebetween 2400 band to T1 (1.544 Mbs/sec). The headend computer 8 thenrebroadcasts the data magazine at an appropriate data rate (preferably9600 baud) across the cable system to all nodes 12 simultaneously toupdate the nodes' databases.

The headend computer 8 is preferably an industrial microprocessor-basedcontroller computer with high capacity magnetic or optic read/widestorage devices. The output of the headend computer 8 is an rf carrierat 74 megahertz (between TV channels four and five). This carrier ismodulated using a simple frequency shift key (FSK) technique, preferablyat a data rate of 9600 bps.

The data modulated 74 mhz carrier is connected in the cable TV headend10 to the existing cable TV plant through the rf combiner along with theregular cable TV channels. As in an ordinary or typical cable TV system,the output of the RF combiner connects to the trunk coaxial cable 24.The trunk 24 is a high quality coaxial cable that forms the backbone ofthe cable system. Trunk amplifiers 26 are placed every quarter mile tomaintain signal strength. At cross streets or where needed, bridgeramplifiers 28 split some signal off of the trunk to supply the feedercoaxial cable 30 which runs down residential streets.

Like the trunk cable 24, the feeder cable 30 has amplifiers, called lineextenders 32, placed every quarter mile--which usually equates to everyten telephone poles. At every telephone pole, and sometimes mid-span,taps 34 are spliced onto the feeder. Each tap 34 usually has from fourto eight outputs to which subscriber drop cables 36 are attached. Thesubscriber drop 36 attaches to the home and then runs inside,terminating at the subscribers' TV sets 38. There are usually two lineextender amplifiers per feeder cable, sometimes there are three amps,but rarely any more for signal quality reasons.

One node 12 is placed at the start of the feeder cable just after thebridger amplifier 28. Additional nodes 12 are placed after each lineextender 32 along every feeder cable 30. As an example, for a largecable system of 100,000 homes with typically 2000 miles of cable feeder,there will be approximately 8000 line amplifiers. Such a system wouldcorrespondingly employ 8000 nodes.

In an alternative embodiment shown in FIG. 2A, the node connected to thestart of the feeder cable 30 can also service homes up to the first lineextender 32 on other feeder cables connected to the same bridgeramplifier 28. If a return path is added, a single node 12 can alsoservice homes on both sides of a line extender 32, as shown in FIG. 2B.Finally, as shown in FIG. 2C, if the line extenders 32 on a feeder lineare upgraded to pass 650 MHz and if a return path is also added, onenode can service all homes on multiple feeders from a single bridgeramplifier 28.

The home user interacts with the system using an infrared remote control40. The remote control signal is received by the Home Interface Control(HIC) 16 atop the user's TV set 38. HIC 16 is connected in series withthe subscriber cable drop 36 (and cable converter box when used) and theuser's TV 38. The user commands are relayed back up the subscriber cabledrop 36 and through the tap 34 back to the node 12 on the pole nearbythe home. This signaling, between HIC 16 and node 12, is done in the 5to 50 MHz band, which is reserved by all cable system for return channelsignaling.

The last node 42 on each feeder 30 has a telephone line 18 attached thatis used by that node to send user responses back to the headend computer8. All nodes along the feeder (usually two nodes) upstream from the endnode 42 send their user responses to the end node 42 via an rf carrierat 74.5 MHz (between channels 4 and 5) at a preferred data rate of 9600bps. To complete the loop, the headend computer 8 sends user responsesback to the regional center 4 via datalink 20.

In summary, the system moves data updates across the cable systemwithout using any cable TV channels by utilizing unused inter-channelspace. The return path for interactive services is up the subscriberdrop to the node at a low frequency, then downstream in inter-channelspace along the feeder cable to the end of every feeder, then telephonelines back to the headend computer and telephone lines again to theregional computer center and telephone from there to the respectiveservice provider. The aggregate delay from user back to service provideris no more than 5 seconds,

VI. Bandwidth Utilized by the System

Referring now to FIGS. 3, 4 and 5, each node 12 broadcasts on up to 32standard TV channels. The 32 channels are broadcast as a block ofadjacent channels above the last used channel of the cable system. Forinstance, if the cable system offers 50 channels of service, then thesystem of the present invention will use channels 51 to 82. Thefrequencies of 462 to 654 MHz would be used by the present invention ona 50 to 450 MHz cable system. If the cable system used 50 to 300 MHzbandwidth, the present invention would use 312 to 450 MHz, etc. Thesefrequencies pass through the tap 34 and any splitters inside the home,but do not pass through the line extenders 32 or bridger trunk amps 28unattenuated. These outband frequencies are unusable by the cable systemfrom their headend because of the bandwidth limitation of the series oftrunk and feeder amplifiers.

The shaded areas of FIG. 4 illustrate the bandwidth usage. The verticalgrey bands passing through 28 and 32 represent areas of minimumbandwidth. For a typical cable system, as mentioned above, thisbandwidth is 300 to 450 MHz. The node 12 exploits the unused bandwidthof the feeder cable 30, taps 34, and subscriber drop 36 to the home,which is a minimum of 600 MHz. This is represented by the horizontalhashed area 44. Each node 12 only services the taps up to the next lineextender 32, which is usually less than twenty taps total and an averageof thirty homes.

Some signals in the 462 to 654 MHz range from the nodes 12 will passthrough line extenders 32, as the line extenders do not have a sharpcut-off at their top frequency--450 MHz in our example. To deal withthis, the feeder inserter 46 contains a low pass filter 48 that sharplyblocks the band above 450 MHz, so that the next node 12 can reuse the462 to 654 MHz frequency range for the next group of taps up to the nextline extender, and so on.

When a user presses a key on the infrared remote control 40, the HIC 16receives the command and modulates it onto an 11 MHz carrier which issent up the subscribe drop 36 through the tap 34, through the feederinserter 46 and into the node 12. The feeder inserter 46 contains anotch filter 49 to block the 11 MHz carrier from going further upstream(left in the drawings) on two-way cable systems that have return pathamplifiers (5 to 50 MHz) installed in the line extenders 32 and bridgeramplifiers 28.

All HICs 16 signal back to their respective node 12 on an 11 MHzcarrier. To avoid contention, the node 12 polls the HICs 16 on 12 MHz ina round-robin fashion. This HIC polling frequency also carries data forthe printer 50 when the user chooses a selection on screen that allowsprintouts, such as store coupons or theater tickets. A third use of this12 MHz carrier is for available channel status from the node 12 to theHICs 16. When the user first picks up the remote control 40 and touchesany bottom, the HIC 16 reads this status word and selects the lowestchannel available, if any. The HIC 16 then signals back to the node 12on the 11 MHz carrier to reserve the channel.

For interactive services, such as home shopping or purchasing tickets,the user responses need to get back to the respective service provider.As mentioned above, the system supports two-way interactivity via achain of store and forward nodes. Assume a user is interacting with theleft-most node in FIG. 4. User responses are transmitted on a 11 MHzcarrier from the HIC 16 and travel up the drop 36 to the node 12. Thenode 12 transfers the users response on a 74.5 MHz carrier to the lastnode 42 on the feeder cable 30. The end node 42 includes a modem 67(FIG. 6A) and transfers user responses via telephone lines 18 to theheadend computer 8, which relays the user responses to the regionalcenter 4, which finally transfers the responses to the respectiveservice provider. The total delay through the network will be less thanfive seconds from user to service provider.

VII. Overview of the Node and HIC

All but one of the channels of the system are interactive. Theseinteractive channels are allocated on a first-come-first-served basis.All channels are scrambled and a channel can only be viewed by the homethat it was allocated to. Once allocated, the channel is descrambled bythe HIC 16 for each respective viewer. A system channel is assigned toone and only one home upon request (the user activates the remotecontrol 40 to request a channel). The channel remains allocated untilthe user releases it or a certain number of minutes pass without anyactivity from the user.

There are enough channels available for any particular node to allow fora 2 to 1 or greater contention. Audio/video rf modules (described laterin connection with FIG. 6B) are inserted (4 channels per module) topopulate a node for the desired contention level.

Once a system channel has been allocated to one of the approximatelyforty homes that can contend for it, the home user interacts with thenode 12 in privacy. The channel is not viewable by other homes. To theuser, the system is a dedicated channel to their TV set. The userinteracts with the system using the remote control 40 to move anon-screen pointer over an icon, text, or image of choice and presses abutton on the remote control 40 marked "PLAY" to select choices andcall-up desired information.

When the user tunes to the system channel, the channel is displaying thelatest TV listings. All subscribers on the cable TV system can see thisservice by just tuning to the cable television channel assigned to thesystem of the present invention. Upon tuning to this channel, the usersees the non-interactive channel of the system. If the user picks up theremote control 40 and touches any button, a request is sent to the node12 for a dedicated system channel. The system then switches to one ofthe up to 31 dedicated interactive channels automatically (assuming oneis available) and the user can begin to use the system, unaware of thechannel change.

The change from the non-interactive display only channel to aninteractive channel is effected by the home interface controller (HIC)16 on top of the user's TV set 38. The home interface controller 16monitors a 12 MHz FSK data stream from the node 12 modulated with apolling command to activate HIC 16 in a round-robin fashion. (Analternate embodiment uses the vertical blanking interval of thenon-interactive channel to receive channel assignment and channelrelease commands from the node).

Since the user typically spends a significant amount of time viewingmenus and other non-moving displays of information in using the system,the virtual channel can be released for use by others during these"dead" periods (when no new information is being received from the node)by installing a frame grabber 39 in each HIC. Thus, the user is assigneda virtual channel only during the short periods that data is actuallybeing transferred from the node to the HIC, making more efficient use ofthe virtual channels and thus avoiding contention problems.

Frame grabber 39, shown in detail in FIG. 8A, consists of frame grabbercontrol logic 202, a video D/A converter 204, a video RAM 206, a videoA/D converter 208, and a NTSC encoder 212. In operation, the framegrabber control logic 202, upon receiving a gating command from CPU 80,activates video D/A 204 at the appropriate time (based upon the NTSCsynch signal) to convert a frame of video into digital data. That frameof data is stored in video RAM 206 at an address supplied by framegrabber control logic 202. The frame of data stored in video RAM 206 isconverted back to video by video D/A converter 208 (under control offrame grabber control logic 202), routed to NTSC encoder 212 and thenout to an A/B switch 41. A/B switch 41, operating under control of CPU80, gates either the video from the virtual channel or the frame ofvideo from frame grabber 39 to RF modulator 98, from where it is gatedto the user's TV as described later. While the A/B switch 41 is gatingvideo from frame grabber 39 to the user, the stored frame of data isrepeatedly read out of RAM 206, converted to video, and routed to theuser's TV. This process continues until the viewer is ready to turn to anew page or screen on his TV.

As shown in FIG. 8, the electronics of the home interface controller 16is designed to convert not only the stored frames of data, but also anyof the available interactive channels, to the same channel as thenon-interactive attract mode channel (channel 1). The HIC 16 alsocontains an infrared receiver that receives commands from the remotecontrol 40. The received commands are modulated onto an 11 megahertzcarrier and sent up the cable from the home back to the node 12 outside.

The remote control device 40 (FIG. 15) is based on battery operated,standard infrared remote control technology. The remote control has atouch pad area 52 where the user presses a finger and causes a pointercursor on the TV screen to move proportionately. The touch pad 52 is awireless analog to a mechanical mouse as used by the Macintoshcomputers, among others.

The system preferably includes a thermal or ink jet printer 50 connectedto the HIC 16, allowing the system to printout on demand hardcopy ofinformation on the TV screen. The printer 50 can also print storecoupons for special promotions. Another intended feature is for theprinter 50 to print theater, sports and concert tickets encoded with aunique universal bar code. These bar-coded tickets can then be scannedat the theater or stadium for validation. Tickets of all kinds can bepurchased over the system with the user entering a credit card numberand PIN code on the TV screen.

To summarize, the system of the present invention is a distributedprocessing based system designed to provide a highly interactive andstimulating environment to the consumer. The system displaysphotographic quality images in both still frame and short full-motionsegments and in both cases with synchronized audio. Because of theability to display photographic-quality images, the system is not basedon any graphics protocol such as NAPLPS or GKS, etc. The systemtranscends the video game-look of current and previous videotex systems.

VIII. Technical Description of Node and HIC

Referring now to FIGS. 5-8, data updates from the headend computer 8 arereceived off of the cable TV feeder cable 30 on a 74 MHz carrier througha directional coupler 58 and splitter 59. The data is demodulated by rfdata receiver/demodulator 62 (at a preferred output data rate of 9600bps) which feeds I/O processor 64. The I/O processor 6 transfers data tosystem RAM 66 which is then read by the CPU 68 and transferred to thelocal hard disk 70. (As shown in FIG. 5, DC power for the node isprovided by a power supply 60 which is driven with AC power from thecable feeder via a power combiner 55).

The node control software places the received data into the systemdatabase and performs several indexing steps to knit the data into theexisting database categories. These categories include product types,product names, company name, category that product or service belongs toetc. In addition, the database update items (advertisement data objects)contain the thesaurus entries that link the database entry (object) intoa hierarchical thesaurus, establishing a network of meaning andassociations amongst the data in the node database.

When a user tunes his or her TV to the system non-interactive channel(usually one channel higher than the highest channel used by the cablesystem), the user will see a non-interactive system channel showing thelatest TV listings scrolling by on the TV screen. The user cannotinteract with this image as the viewer is watching an attract mode onlychannel (system channel one at 462 MHz). All viewers on the cable TVsystem can see this channel simultaneously, whether they have a homeinterface controller 16 installed or not in their home. The homeinterface controller 16 has a trap 72 to block this channel, but thetrap 72 is shunted by an rf switch 74 allowing the signal to pass untilthe user picks up the remote control 40 and presses any button. The r/ccommand from the user is received by an infrared receiver 76 mounted onthe HIC box atop the TV set. This signal is demodulated by remotecontrol receiver/demodulator 78 and passed to the HIC CPU 80.

The HIC CPU 80 starts the process of acquiring an interactive, dedicatedsystem channel--so the user can interact with the system--by reading astatus word from the data stream sent by the node 12 down the subscriberdrop 36 on a 12 MHz carrier. This carrier is picked up off of thesubscriber drop 36 through directional coupler 82 and throughsplitter/mixer 84. RF data receiver 86 detects and demodulates thesignal into a serial data stream which feeds a CPU I/O port. The HIC CPU80 reads the status byte and selects the lowest available interactivechannel number (1 of 31). If all channels are busy, which should be arare event, a red indicator 88 lights to indicate busy. The HIC CPU 80will continue to watch the status word until a channel is available.When a channel is available and live, the HIC CPU 80 lights a green"ready" light 90. Assuming a channel is available, the node 12 willassign the channel to the requesting HIC 16. The HIC CPU 80 will addressthe assigned channel on the programmable channel tuner 92. The tuner 92demodulates the channel from rf to video. However, none of theinteractive channels are broadcast with video sync information and are,therefore, scrambled and unviewable on an ordinary TV set.

All 32 system channels are synchronized by the same video sync generatorin the node 12. To reapply video sync to the interactive channels, theHIC 16 extracts sync from the attract mode channel. This is done bychannel tuner 93, which is always tuned to non-interactive channel 1 at462 MHz. The tuner 93 demodulates system channel 1 and passes thecomposite video signal to a NTSC sync extractor 96 which then providessync to a NTSC sync adder 97, reconstituting the interactive channel tofull composite video.

Once resync'd, the interactive channel video is modulated by rfmodulator 98 to system channel 1's frequency (462 MHz). The CPU I/Ocauses RF shunt 74 to open, allowing the 462 MHz notch filter 72 to takeeffect, removing the attract mode channel. The inverse of this I/Ocommand gates on the RF modulator 98, placing the interactive channel onthe same frequency. To the user, nothing has happened, other than thescreen having changed to the initial menu. The user may now interactwith the system.

There are 31 interactive channels utilizing the spectrum from 468 to 654MHz. These interactive channels are created from images and sound froman advertisement data object stored in RAM memory 100 in the node 12.The data object is placed in RAM 100 as the system determines the needto display information or images and play sounds. The data object to bedisplayed is called off of the hard disk 70 and placed in system RAM 66.The data object contains compressed video and audio components. The CPU68 reads a compressed image out of RAM 66 and passes the image throughthe image decompressor 102. The output of the decompressor 102 is put inRAM 100. The same process is applied to audio tracks from anadvertisement data object. As with the video component, the audio trackis read off the disk 70 in a compressed form. The CPU passes thecompressed audio to the digital signal processor (DSP) 102 fordecompression and then passes the uncompressed digital audio to RAM 100.

The video sync generator 104 drives the video display logic 106 whichclocks the digital image out of memory and through a video digital toanalog converter 108, producing an analog video waveform. The digitizedaudio track is clocked out of memory when required and applied to anaudio digital to analog converter 109. The audio processing takes placein the audio processing logic section 110. The video and audiocomponents are encoded in the NTSC encoder 112 to create a broadcastquality video signal applied to RF modulator 114. Although the NTSC syncgenerated in video synch generator 104 is combined with the video andaudio components for timing purposes in order to perform proper NTSCencoding, the sync signal is thereafter suppressed from the interactivechannels (i.e., all channels except for channel 1) by sync suppressors115. As mentioned above, the absence of sync from these channelsprevents users from viewing a channel dedicated to another home.

The output of the RF modulators 114 are applied to the RF combiner 116,which acts an RF mixer to produce a broadband signal of the combinedchannels. The combined channels are then passed through a mixer/splitter118 in the feeder inserter 46 (FIG. 5) and inserted onto the feedercable 30 through a directional coupler 120 to passed down to the taps 34and down the subscriber drops 36 to the homes.

The node extension interface control 122 is logic to couple the CPU 68with a node extension module 124 (FIG. 7). The extension module 124provides 16 additional interactive channels and is required for the full32 channel (31 interactive) capability described above, since each CPUcan only handle 16 channels. Ordinarily, 16 channels (15 interactive)can adequately handle 40 homes on a contention basis; however, 31interactive channels are required in high density areas of the cablesystem such as apartment buildings. The output of the node extensionmodule 124 connects to the RF combiner 116 of the primary node throughdirectional coupler 126.

IX. Alternative Embodiments

Various alternative embodiments of the present invention are possible.In one alternative embodiment shown in FIG. 9, much of the circuitryfrom HIC 16 is removed and transferred to the tap, specifically to a tapinterface 128. FIG. 10 shows the node electronics for this embodiment ofthe invention. Only the attract mode channel electronics remain in thenode 12; as shown in FIGS. 11A and 11B, the tap interface 128 nowcontains the electronics for the interactive channel, but there is onlyone such channel, and this channel must be shared on a contention basisbetween the four homes normally connected to the tap. Tap interface 128also contains notch filters for connecting the single interactivechannel to the first home that selects it, while the other homes remainconnected to the non-interactive channel.

In a further embodiment of the invention shown in FIG. 12, tap interface128 contains separate processing electronics for each of up to 60 homesconnected to the taps associated with a node. In this embodiment, thereis never any contention between homes for the data stored in the node.This should be contrasted with the first preferred embodiment of theinvention, where there is some contention, but only up to 32 sets ofprocessing electronics are required, one for each channel.

In yet still another embodiment of the present invention shown in FIG.13, all of the node electronics is provided in the HIC 16 of each home.In this case, each HIC 16 would include essentially all of theelectronics shown in FIG. 10 but, as in the embodiment of FIG. 12, thereis no contention whatsoever between homes.

X. Infrared Remote Control

The infrared remote control device 40 preferably used in the presentinvention is shown in greater detail in FIG. 15. The touch pad area 52of the device consists of a membrane switch array 132. In its inactivestate, all outputs of 1 of 16 demux 134 are on, sensitizing all verticalcolumns of array 132. When the user touches any point on the array, theclosure of a switch is detected by 1 of 16 mux 136, causing the outputport labelled "ANY OUT" of 1 of 16 mux 136 to go high and thusactivating timer 138. The high output from timer 138, in turn, activatesgated oscillator 140 and deactivates the continuous "all on" state of 1of 16 demux 134, initiating the scanning and reading of the columns androws, respectively, of array 132, via 4×4 matrix counter/scanner 142.The switch closures detected by scanner 142 are encoded with acorresponding touch pad position (based upon the timing of the scanning)by parallel to serial Manchester encoder 144, and the encoded signal issent to infrared transmitter 146.

Referring to FIG. 19, the infrared remote control device 40 is alsoadapted to receive infrared signals sent from an infrared transmitter 77on remote control infrared transceiver 78 in HIC 16, and re-emit thesereceived infrared signals to other electronic devices within range.Thus, for example, a user can program the node 12 (using on-screencommands via infrared remote control device 40) to turn on a TV or VCRto a preselected channel at a preselected time. The node 12, which hasstored in its memory the individual infrared command signals for allpopular electronic products, sends the appropriate command to HIC 16 atthe preselected time, and the command is emitted from infraredtransmitter 77 to infrared remote control device 40. An infraredreceiver 147 on infrared remote control device 40 receives the command,a header on the command is recognized by CPU 145, and the CPU 15 causesthe command to be re-transmitted by the infrared remote control device40, via Manchester encoder 144 and infrared transmitter 146, to the TVor VCR to be activated. Alternatively, the HIC 16 can transmit directlyto the device to be controlled by bouncing the command signal off a farwall or off any appropriate reflective surface which is properlyoriented. In the above fashion, the present invention can be utilized asa universal remote control device.

XI. Demand Side Management/Automated Meter Reading

The present invention can also be used to control and/or read devices inthe home using power line carrier technology. For example, a user canprogram the system to turn on a lamp in his house at a certain time byinputting appropriate commands through the remote control device (thenode leads the user through the use of this feature with interactiveinstructions)--the user's commands are sent out to the node by the homeinterface controller and stored there. At the time programmed foractivation, the node sends an instruction to the user's home interfacecontroller to turn on the lamp, and the home interface controllerimplements that instruction by communicating with the electrical outletfor the lamp over the home's power line.

Likewise, the utility company can use this feature of the invention fordemand side management, e.g., to temporarily turn-off the airconditioning compressors, hot water heaters, or other high powerappliances of its customers during periods of high usage to avoidbrownouts. Moreover, using power line management, the utility companycan control the high-power appliances of not only users of the system,but also those of the neighboring homes. Since four homes typicallyshare a transformer, and since about 60% of all homes are wired forcable, the utility company should be able to control virtually all homesin a neighborhood using the present invention.

XII. Optional Features

Optionally, as shown in FIG. 16, the system of the present invention canbe provided with an interface unit to allow the user to plug in aconventional PC keyboard 150, and thus enter alpha-numeric commandsdirectly without the use of IR remote control 40. The unit provided tothe user includes a standard PC board connector, keyboard scan logic152, a remote control modulator/driver 154 and an infrared diodetransmitter 156.

Alternatively, users who do not have PC keyboards or who want adedicated keyboard for use with the system can be provided with aspecial touch pad unit 40 which includes a full alpha-numeric membraneswitch keyboard in addition to the touch pad area 52 shown in FIG. 15.

Another available option, shown in FIG. 17, is an interface to allowusers to input video for classified ads to be transmitted over thesystem. This unit consists of a receptacle 158 for inputting video froma camcorder or VCR and a video to RF modulator 160 in the HIC 16 of theuser. An RF to video demodulator 162 and a video digitizer 164 areprovided in the node 12 to demodulate and digitize the video data, whichis then forwarded to the regional processing center in the mannerdescribed previously.

A still further option, shown in FIG. 18, is an autodialer provided inHIC 16 to automatically dial up a merchant or classified advertiser fromthe screen to allow the user to speak directly by telephone, to theseller. A CPU 166, through a telephone company subscriber line interface168, automatically places the call for the user.

XIII. Providing Supplemental Information from a Node Regarding ProductsAdvertised During Commercials

The nodes of the present invention can be programmed in advance tocontrol the home interface controllers to display insert text overlayson the television screens of users watching specified televisionprogramming, asking those users whether they are interested in receivingadditional information about a product being advertised. If a userresponds affirmatively (via his remote control device), the homeinterface controller of that user passes the affirmative response ontothe node, and the additional information requested is placed in theuser's electronic "mailbox" at the node. When the user checks hismailbox at a later time, he will see that the additional information isavailable for viewing.

XIV. Providing Customized Advertising from a Node During Commercial Timeof Cable Programming

The nodes of the present invention can also be programmed to providecustomized advertising to users of the system during the commercial timeof ordinary cable television commercials. In this embodiment of theinvention, users watching a particular program would automatically beswitched to a virtual channel over which a commercial customized fortheir particular demographic location would be transmitted. Thecustomized commercial would be transmitted from the node to the userover the virtual channel during the 30 second or 1 minute intervaltypically allocated for advertising during the programming. At the endof the commercial time, the user would be returned from the virtualchannel to the original channel, and normal programming would resume. Inthis manner, advertisers could prepare a variety of commercials targetedto different demographic groups, such that the commercial viewed by oneclass of users would be customized to the interests of those viewers,while other viewers would see a different commercial customized fortheir purchasing habits. Again, the switching of the system from theoriginal programming to a virtual channel and back to the originalprogramming would be transparent to the user, the switching beingaccomplished utilizing synchronization information received from thebroadcast network and transmitted from the headend computer to the nodeover a data channel.

XV. Distributing Programming from an External Source Through a Node

Referring to FIG. 20, a node 12 can be fitted with a satellite and/or RFreceiver 170 to receive and transmit programming down to that node'sfeeder 30 over virtual channels. In this manner, additional programmingcan be provided to users of the system without utilizing the alreadycrowded cable TV channel space. Likewise, a node 12 can be directlycoupled to the headend via fiber optic cable or conventional coax cablefor retransmission of particular programming or for access to databasemanagement systems.

A node 12 can also receive programming from a local video source 172(such as a video rental store) coupled to a tap downstream of the node.The video source 172 transmits to the node over the upstream frequencyband of 5-30 MHz (the same frequency band as user commands), so thesignals can pass upstream to the node. The node 12 converts the receivedvideo to the higher frequency of the virtual channels for transmission,upon request, to users down the feeder.

TV Channel Decompression

The nodes of the present invention can also be used for decompressingcompressed TV channels and distributing the decompressed TV channels tothe homes connected thereto. This use of the invention allows the cableTV company to transmit an expanded number of channels without having toinstall expensive decompression circuitry in each home or upgrade thecable TV system plant.

In this embodiment of the invention, the less watched TV channels arepreferably compressed at a ratio of four to one and transmitted from thecable TV headend on ordinary TV channel slots, with four channels ofcompressed TV signal being sent in the space of one uncompressedstandard channel. The compressed TV signals are decompressed intoordinary receivable TV channels at decompression nodes distributedthroughout the cable TV system. When a user requests one of thesecompressed channels, the decompressed channel is transmitted from thedecompression node to the HIC of the user over a virtual channel.

Current systems such as Jerrold (General Instrument) DigiCable or SkyPixmovie system place an expensive converter in each subscriber's home todecompress and display compressed channels. In the present invention,the expensive decompression logic is placed in the node serving 20 to100 or more cable subscribers. When a user requests a compressedchannel, that channel is decompressed in the node and retransmitted tothe user in "virtual channel space" or in space previously occupied bythe compressed channels. If multiple users request the same compressedchannel, their HIC is assigned to the same virtual channel on which thatdecompressed channel is already being transmitted.

Referring to FIGS. 21-25, various bandwidth utilization schemes can beused depending upon the density of subscribers serviced in a particulararea. For example, FIG. 21 shows the bandwidth utilization schemepreferably used in a low-density suburban area, in which the 12 basicchannels (Channels 2-13) are transmitted uncompressed to all homes, and80 compressed channels are transmitted by decompression nodes located atthe bridger amps to each of the approximately 50 cable households servedby that node in the 20 standard channel space above channel 13. Asstated previously, the electronics are configured such that more thanone user can view the same virtual channel on which decompressed videoprogramming is being transmitted. Thus, it is possible that all 50 userscould be watching decompressed channels at the same time withoutconflict, so long as no more than 20 different decompressed channels arechosen for viewing at the particular time.

FIG. 22 shows a scheme best suited for a high-density suburban area inwhich each node serves approximately 100 households. Like the embodimentof FIG. 21, the decompression node is located at the bridger amp only,but in this case the decompressed programming is transmitted over 40virtual channels, which allows 40 homes at a time (out of a 100) to eachrequest one of 80 compressed channels. Again, multiple users cansimultaneously view the same decompressed programming. This isaccomplished by increasing the frequency response of the line extendersalong the cable TV feeder legs.

FIG. 23 shows yet another bandwidth utilization scheme for an evenhigher density area, such as an urban street or apartment house. In thisembodiment, decompression nodes are situated along the feeder 30, suchthat each serves about 100 homes. Decompressed programming istransmitted by each of the decompression nodes on 30 additional channelsabove the typical 32 standard channel space. At each decompression nodedown the feeder, a low pass filter 176 is provided to block the virtualchannel space, so that those same virtual channels can be used fortransmitting virtual channels to the next 100 homes down the linewithout interference from neighboring nodes.

Finally, referring to FIGS. 24 and 25, analogous bandwidth utilizationschemes are shown in which all cable television channels are allowed topass through the system and are available to all users, and decompressedprogramming is transmitted in the space above the highest channel usableby the cable television system. However, in this case, the compressedprogramming must be sent to the node from an external source (such asvia the satellite receiver 70, radio frequency or fiber optic link shownin FIG. 20).

Frequency hopping scrambling may be employed at the node to preventunauthorized access to the decompressed channels distributed by thenode. In this embodiment, the frequency of the decompressed channelsoutput by the node is changed periodically (the change being made duringthe vertical blanking period) by a random number generator (thus one ofthe uses for frequency agile RF modulators 196 as shown in FIG. 28B).Each of the home interface controllers contains an identical randomnumber generator which is seeded identically with the node fordescrambling the frequency scrambled signal. Alternatively, the node cansupply the channel hopping commands to the HIC to keep the HIC in synchwith it. These commands can be scrambled for high security using anycommon scrambling technique, such as DES scrambling. In such a case,each home interface controller would contain a descrambling "key", whichwould be updated periodically by the node.

XVII. Distributing Information and Programming from a Headend ThroughDistribution Nodes

Referring to FIG. 27, the nodes 12 of the present invention can belocated at a central location, such as a headend, and transmitinformation and programming via coaxial or fiber optic cable todistribution nodes 190 located on feeders adjacent at the cable TVbridger amplifiers 28. As shown in FIGS. 28A and 28B, distribution nodes190 contain only the electronics necessary for frequency conversion,assignment of virtual channels and video compression/decompression--thebulk of the processing and data storage is now in the nodes 12 at theheadend.

In operation, user commands are sent to the distribution node 190, wherethey are transmitted by RF modem 191 over the coax or fiber optic cableto the headend. The headend allocates a channel for transmission of therequested information and/or programming to the distribution node 190,and also a virtual channel for transmission from the distribution node190 to the home of the user. Control data identifying those channels issent from the headend to the distribution node 190, where it isdemodulated by RF modem 197 into a digital data stream which feeds I/Oprocessor 64. The requested information and/or programming is then sentto distribution nodes 190 from headend node 12 through the fiber or coaxcable over a typical frequency band of 50-450 MHz (this frequency bandis available to the system since the fiber or coax is not used by thecable TV company).

As shown in FIG. 28B, RF tuners 192, under control of the distributionnode CPU, receive the channel transmitted by the node 12 at the headendcontaining the requested programming and/or information. If the requestis for programming and the programming has been compressed at theheadend, it is decompressed in distribution node 190 by videocompression-decompression processors 194. The decompressed programmingis then encoded by NTSC encoders 112 and modulated by frequency agile RFmodulators 196 to the frequency of the assigned virtual channel. Theinformation or programming is then transmitted from the distributionnode 190 to the user.

The central storage of data at the headend is particularly advantageousfor distributing user video throughout the system. As shown in FIG. 28C,user video from a home interface controller enters distribution node 190through diplex filter 118 and is placed on the same line as RF from theheadend (FIG. 28A). RF tuner 192 captures the user video (FIG. 28B) andsends it through video compression processor 194. The compressed uservideo is then modulated by RF modem 193 and is sent out through diplexfilter 195 onto the fiber or coax to the node 12 at the headend (priorto this transmission from distribution node 190 to the headend, controldata identifying the channel to be used for the transmission is sentfrom headend node 12 to CPU 12 of distribution node 190, which in turncontrols RF modem 193). At the headend, the compressed video can beaccessed (and decompressed) by any user of the system coupled to thatheadend. In this manner, the present invention can be used for videoteleconferencing. Note that the video compression/decompressionelectronics of node 12 at the headend performs the inverse function ofdistribution node 190 using the same architecture.

XVIII. Transmission Over Fiber Optic Cable

In areas where the telephone company serves homes directly withfiber-optic cable, the nodes of the present invention can be placed inthe remote terminals of a telephone company fiber optic system.

Referring to FIG. 26, nodes are disposed in each of remote terminals 180and insert a time domain multiplex (TDM) channel in the time-slice ofthe respective home when the user requests an interactive channel orother desired programming. The requested information or channel istransmitted over fiber 181 to curb-side pedestals 182, and distributedfrom there to each home 18 over coax cable 185. The nodes 12 receiveupdates from a store and forward computer 186 located in the centraloffice of the telephone system (analogous to headend computer 8 of thecable TV design) over the typical 1.2 GHz fiber coupling the telcocentral office to each remote terminal.

Although the present invention has been described in relation toparticular embodiments thereof, many other variations and modificationsand other uses will become apparent to those skilled in the art. It ispreferred, therefore, that the present invention be limited not by thespecific disclosure herein, but only by the appended claims.

What is claimed is:
 1. A system for transmitting video pictureinformation to home televisions over a fiber optic telephone system,comprising:means for distributing said video picture information oversaid fiber optic telephone system; and a plurality of nodes, eachassociated with a plurality of subscribers viewing said hometelevisions, each of said nodes being coupled to said fiber optictelephone system for capturing and storing said video pictureinformation transmitted over said fiber optic telephone system and fordistributing said video picture information, upon demand, to saidsubscribers associated therewith, wherein said subscribers viewing saidhome televisions can display and interact with said video pictureinformation stored in said associated node by communicating to saidassociated node, said associated node containing a substantiallycomplete copy of said video picture information which said subscriberscan display and interact with, such that said subscribers interactdirectly with said video picture information stored in said associatednode, said video picture information including full-motion videoinformation.
 2. A system as recited in claim 1, wherein said associatednode is disposed in a remote terminal of said fiber optic telephonesystem.
 3. A system as recited in claim 1, wherein said associated nodedistributes said video picture information over fiber optic cable tocurb pedestals associated with said subscribers.
 4. A system as recitedin claim 3, wherein said curb pedestals each include an optical networkinterface and are coupled by coaxial cable to the home televisionsassociated therewith, said video picture information being transmittedfrom said associated node to said subscribers over said coaxial cable.5. A system as recited in claim 2, wherein said means for distributingsaid video picture information over said fiber optic telephone systemcomprises a store and forward computer located in a central office ofsaid fiber optic telephone system, said central office being coupled tosaid remote terminal by fiber optic cable, said store and forwardcomputer distributing said video picture information to said associatednode in said remote terminal over said fiber optic cable.
 6. A system asrecited in claim 1, wherein said video picture information istransmitted to said subscribers by said associated node over a timedomain multiplex (TDM) channel.
 7. A system as recited in claim 1,wherein each of said subscribers viewing said home televisions cancommunicate, to said associated node, a request for selected videopicture information from said associated node, said associated nodeincluding:(i) means for dynamically assigning one of a plurality ofchannels to the subscriber requesting the selected video pictureinformation; and (ii) means for transmitting said selected video pictureinformation to the home television of the requesting subscriber over theassigned channel.
 8. A system as recited in claim 7, wherein each ofsaid home televisions includes an associated home interface controllerwith means for receiving said selected video picture informationtransmitted by said associated node over said assigned channel.